Night vision devices are commonly used by pilots to enhance their visibility while flying during night or other low-light conditions. Conventional night vision devices include image intensifier tubes, lens assemblies, battery packs and adjustable mountings that provide the night vision devices with a significant mass. In the prior art, the mass of a night vision device is conventionally supported in front of the eyes of a pilot either by attaching the night vision device directly to the pilot's helmet or attaching the night vision device to a goggle assembly that is strapped around the pilot's helmet. A prior art helmet mounted night vision device is exemplified in U.S. Pat. No. 4,449,787 to Burbo, et al., entitled NIGHT VISION IMAGING SYSTEM ADAPTED FOR HELMET MOUNTING.
When a pilot ejects from an aircraft, large acceleration forces are developed as the pilot is suddenly propelled away from the aircraft. For this reason, it is highly desirable to detach the night vision device from the pilot's head prior to ejection. By detaching the night vision device from the pilot's head, the mass of the pilot's helmet is reduced. This reduces the chance of injury to the pilot's neck during the sudden accelerations incurred during ejection. Furthermore, by selectively detaching the night vision device from the pilot's helmet, the night vision device is prevented from colliding with the pilot's face during ejection. In the prior art, many release mechanisms use pyrotechnics to separate night vision devices from a pilot's helmet. However, many pilots are not comfortable with the thought of having an explosion charge connected to their helmets.
The prior art does contain some night vision devices that separate from a pilot's helmet in a non-explosive manner. Such an apparatus is exemplified by U.S. patent application Ser. No. 07/990,061 to Holmes et al, entitled HELMET MOUNTED NIGHT VISION APPARATUS AND METHOD OF SEPARATION, which is assigned to ITT Corporation, the assignee herein. In the Holmes application, the night vision goggles disengage from a pilot's helmet by rotating away from the helmet across an arc of approximately 45.degree.. The rotation of the night vision goggle assemblies across this arcuate path takes a relatively long period of time considering the rapid dynamics that occur when a pilot ejects from his/her aircraft. If the night vision goggles are not ejected in a rapid enough fashion, the ejecting pilot may be ejected before the night vision goggles separate, thereby potentially causing injury to the pilots neck.
It is therefore a primary object of the present invention to provide a night vision device that separates from a pilot's helmet in both a non-explosive and highly rapid manner and allows the night vision device to be completely separated from the pilot's head before the pilot is ejected from the aircraft.